murray



Dec. 3, 1940.

T. E. MURRAY BOILER Original Filed Oct. 9, 1925 5 Sheets-Sheet 1 4 INVENTOR 730M615 A: M0669); was 6) 1055199 5 Muff/9) B1 (J.}A. MATTORNEYS T. E. MURRAY BOILER 5 Sheets-Sheet 2 Original Filed Oct. 9, 1925 THO M 95 5 MU? l/ll/I/l/l/lluI W H1 /l/l/l/l/l/l/ldl/ 1 m vMA. g a w 6 NM mm M a m BY M ATTORNEY:

Dec. 3, 1940. 1-. E. MURRAY BOILER 5 Sheets-Sheet 3 Original 'Filed Oct. 9, 1925 v y 1 v v y y v 1 I Y7 VEN TOR 05054550 BY Mm ATTORNEYS Dec. 3, 1940. r. E. MURRAY 21549 BOILER 7 Original Filed Oct. 9,'-192s {Sheets-Sheet 4,

56 I r I 3 37 ATTORNEY;

Dec. 3, 1940. T. E. MURRAY 9 BOILER I Original Filed Oct. 9, 1925 5 Sheets-Sheet 5 I BY a! M ATTORNEYS Reissued 3',

UNITED STATES ln certaln previous applications, particularly No. 642,725, patented February '11, 1930, Patent No. 1,746,711, there has been described. boilers having walls or banks of water tubes exposed 5 to the direct radiant whereby the rating or production of steam is very much increased as compared with boilers of previous types.

The present invention is directed to a boiler in which this principle is utilized to the fullest possible extent, and is directed to various other features described in detail hereinafter. The accompanying drawings illustrate embodiments of the invention. I Fig. 1 is a perspective view, partly broken away to show the interior, of a system oftubes arranged on the sixsides of a rectangular furnace or combustion chamber; Fig. 2 is a horizontal section showing the tubular walls surrounded by refractory material and a supporting structure;

.fired boiler; Fig. 5 is a horizontal lower part of one of the boiler walls; Figs. 6 and 7 are partial horizontal sections illustrating modifications; Figs. 8, 9 and 10 are vertical sections illustrating difierentpaths of the hot gases passing out of the combustion chamber.

Referring first to Fig. 1, there are front walls I, back walls 2 andside walls I composed of vertical tubes spaced apart with flanges extending across the spaces, and 'similar'longitudinal tubes arranged to form atop wall 4 and bottom wall 5. 'The firing nozzles or grate and the passages for the gases are omitted from this figure, as are also the surrounding walls of refractory material. These details may other figures.

The tubes of and of the bottom wall 5 lower ends with headers 6 and 'I,. The tubes of the opposite side walls 3 communicate with bottom headers l which are connected at their ends to the ends of the headers 6 and 1. A

communicate at their -mun1cates' with the tubes 4 of the top wall and also with the ends of the, upper headers Ill of the side walls. A steamfidrum ll receives steam directly fromthe tubes of the front wall I and of the top wall 4 and also from the upper headers Ill. The steam is taken oil! from the drum in any usual way. 'The water from the drum out of its ends by down-comers 12 to the lower headers 9. The tubes and headers which aims I som 1 I Thomas E. um, ite

N. E; by Joseph 3. Murray, and Thomas E. Hurt",

executors, assignon, to Me 7 in; Company. a corporation of New York I I Original No. 1993,0112, 5. 1985.8!!! October 9, .1925, Application for reissue March 4, 1937, SerialNo. 128,973

' '22 Claims. (oi. neg-23s heat of the burning fuel,

Fig. 3 is a section on the line 3-2 of Fig. 2; Fig 4 is a vertical section of a stokersection of the be varied in design and arrangement, as illustrated, for example,,in the the front and rear walls I and 2 a header on the upper ends of the tubes 2 com- PATENT oar-ice Brooklyn, Brooklyn, N. 1., Br ok -3.1..

trop'olitan Engineerare shown horizontal may be slightly inclined upward in the direction of flow if preferred, and the circulation may be provided for in various other ways. l

The water entering the lower headers 9 passes into the headers 6 and I, the bottom wall and the lowerends of the front, back and side wall tubes. Thence the wet steam and water pass 'upward to the headers 9 and II, the top wall 4 and the upper end of the front wall I, where theypassintothedrumll.

The fuel is burned in the combustion chamber enclosed by the tubular walls, so that all the tubes are exposed to the. direct radiant heat of theburning fuel and steamis generated at a 15 very high rate and very efficiently.

As illustrated in Fig. 2, the individual tubes II are provided each with two flanges I4 overlapping those of theadiacent tubes, so as to subleaving the tubes free to expand or contract independently of one another, and to be separate- 1y renewed when necessary. A layer or wall of refractory or insulating material is arranged outside of the tubes. Preferably. this consists of plastic insulating material l5 tied to the tubes by means of, flanges IS 'on the, latter having lateral extensions ll embedded in the plastic material. The flanges ll and 16 are secured to the tubes by welding, or other methods.

7 Outside of the plastic material Ii there is (see. Fig. 5) preferably a facing ll of cement and a steel plate ll fastened by means of anchors 20 embedded in the insulating material and out of contact with thetubes to avoid conduction of heat therefrom.

The vertical walls of the boiler made as described are preferably surrounded by a wall of brickwork or other masonry 2| built up against an insulating plate 22 and a steel plate 23 bolted stantially close the space between them, while 20 to columns 24 which support the roof of the boiler or other parts of the surrounding structure. The space 25 between the outer and inner walls serves as an insulating air space and -may also be used as a pre-heating passage for the air used for combustion. 7

In some boilers it is desirable to protect parts of the inner face of the water walls from too great heat or, for other reasons, to interpps'e a shield between parts of the tubing'and the combustion chamber. In such cases the parts of the tubes to be shielded are provided with. anchoring means suehfor example as .the flanges 26, preferably having lateral extensions 21, and

a layer of plastic 2| is applied. em-

therewith as in Fig. 5.

. burners or nozzles are arranged in sets of two or gases from the boiler In Fig. 4 the entire bottom wall is occupiedby a stoker The line 3| indicates the top of the refractory protecting material 28. This part of the side walls and rear end wall is practically in immediate contact with the fuel. The shield 29 prevents burning out of the tubes and also prevents undue cooling of the fuel.

Fig. 6 illustrates certain modifications in detail. Tubes 32 are used without flns, the spaces between the tubes being fllled by refractory bricks 33 shaped to provide grooves for the tubes and to constitute an enclosing wall.

Fig. 7 also illustrates an enclosing wall of refractory bricks 33. The tubes 34 in this case are provided with overlapping flanges 35 (similar to those in Fig. 5), but without flanges to tie in the refractory material.

The materials which have been referred to herein as refractory" are not necessarily adapted to withstand extremely high temperatures, as the term is often understood in the art of furnace construction. They need be only sumciently refractory to withstand the temperatures to which they are severally exposed; which for some of these materials are not very high.

Instead of using a grate flred boiler it is preferred to use pulverized coal or similar jet fuel introduced through nozzles 36 (Fig. 2), arranged to inject the fuel in jets at difl'erent angles so as to secure a thorough admixture during combustion and a uniform distribution of the gases against the different water walls. Preferably the more 36 and 31 grouped together as in Fig. 3 to provide for a wide variation in capacity of the boiler. When running at the highest rating all the nomles in a group will be used. For a lower rating a smaller number of nozzles in each group may be used, securing the same velocity of the jets for a decreased quantity of fuel.

Fig. 8 shows an arrangement of the nozzles at the lower end of the chamber and the exhaust proper passing by an outlet 39 to and around tubes 39, a baii'ie 43 and tubes II and thence out by a flue 42. The tubes 39 and II may be any supplementary heating devices such as economizers, air heaters or or even supplementary boiler tubes.

According to Fig. 9., the fuel is admitted at the top and the waste gases pass downward as indicated by the arrows to supplementary heating tubes 43 and 44, and thence out by way of flue 45.

According to Fig. 10, the fuel enters at the top burners of the type illustrated in Figs. 2 and 3. The coal or other ,fuel burned in suspension produces a certain quantity of ash, which is allowed to fall through the spaces between the floor tubes. The chamber, as a whole, then is closed except for 29 on which the coal is indicated at 33.

super-heaters,

horizontal tubes 1 the distance 21,649 bedding the flanges 26 and being thus reinforced openings which admit the fuel and those which permit the passage of the products of combustion, ash at the bottom and exhaust gases at the top. Similarly, in the grate flred boiler of Fig. 4, there is a swinging gate at the bottom, which opens to dump the ash.

Various other usual or suitable provisions for admitting the fuel and discharging the products of combustion may be used. The passage for the exhaust gases may also be in another one of the six walls (four sides, top and bottom). Fig. 8, for example, shows the exhaust gases going out at the top; Fig. 9, at one side and Fig. 10 at the bottom. The tubes-which constitute the walls are exposed to radiant heat of the burning gases. The supplementary tubing shown in Figs. 8, 9 and 10 is heated by convection, that is by the passage over them of the exhaust gases from the combustion chamben Even the lower partof the tubing in Fig. 4 is halted by ,the radiant heat of the fuel bed and the flames above it, although the heat has to be transmitted through the protecting layer of plastic material.

There is a considerable advantage in having the convection tubes outside of the combustion chamber and in such a position as to be shielded wholly orlargely from the radiant heat. -The side walls are of a solid construction as illustrated, for example, in Fig. 2. The burning of the fuel therein tends to deposit and maintain a coating of slag on the tubes which builds out to a thickness dependent on the conditions. The high temperature melts the mineral matter in the flame, particularly in the case of powdered coal burners. The liquid ash or slag coming into contact with the water tubes is cooled therebysufliciently to adhere to them. As the coat thickens the cooling effect of the water in the tubes is diminished. The wall builds out to a thickness such that its surface is so hot that the molten slag runs down the face of it; the heating effect of the flame and the cooling efl'ect of the water being approximately balanced. Such a coating oiiers no substantial objection within the .combustion chamber. It protects the tubes from excessively hot flames and protects the flames from the cooling effect of the water walls.

The same conditions, however, do not apply to convection tubes such as are shown, for example, at 39 and II inFig. 8, l3 and N in Fig. 9 and 46 and 41 in Fig. 19. These tubes are necessarily spaced apart providing passages between the tubes. They are remote from the flames and are shielded from the direct radiant heat of the flame at least to such an extent as to prevent any sub-- stantial accumulation of slag on the .tubes such as would block the passages betweenthem. This is particularly importantv in connection with the 39, Fig. 8. With vertical tubes as in Fig. 9, any slag tends to run down and so to leave the convection passages clear; the result depending-finally on the heat and operating conditions. Where the convection tubes are horizontal or at such a slight angle to the horizontal as not to cause a downllow of slag thereon, it is important that they be arranged so as to prevent the forming of slag thereon.

This arrangement has particular advantages in installations where it is desired to use a flame of extreme intensity. Such a flame causes continuous slag'ging on the side walls and ensures the maintenance of a coating thereon. But the higher the temperature of the flame, the greater to which its slag-depositing effect extends. By protecting the convection tubes from the radiant heat, therefore, the furnace can be run much hotter than if there were no such protection. Any ash remaining in the stream of hot air will fail to accumulate on such convection tubes. It will be so dry as to fall off the tubes or to be carried through the spaces between the tubes with the gas stream.

Various other modifications may-be made by those skilled in the art, without departing from the invention as defined in the following claims.

What is claimed is:

1. A boiler having a combustion chamber all the side walls of which comprise separate upright steam generating tubes, each wall being closed to prevent the passage of the heating gases between the outermost'tubes of the walls adjacent to it so as to form a complete enclosure with each of the tubes exposed to the radiant heat of the burning fuel.

2. The boiler of claim 1 in combination with refractory material on the outer sides of the tubes and projections on the tubes embedded in the refractory material and tying it to thetubes.

3. The boiler of claim 1 in combination with headers at the top and bottom respectively of said tubes, the headers at the bottom being in direct communication with each other and those at the top being in direct communication with each other.

the side walls of which comprise separate upright steam-generating tubes, each wall being closed to prevent the passage of the heating gases betinuously between the ends of the'walls adjacent to it so as to form a complete closure with refractory material on. the outer sides of the tubes and tied to the tubes.

5. A boiler having a combustion chamber all the side walls of which comprise separate upright steam-generating tubes, each wall being closed to prevent the passage of the heating gases between between the ends of the walls adjacent to it so as to form a complete closure, in combination with refractory material on the outer sides of the tubes and projections on the tubes embedded in such refractory material and tying it to the tubes.

6. The boiler of claim 5, and refractory material on the inner sides of the tubes covering only the lower portion thereof, leaving the upper portion exposed directly to the heating gases.

'7. A boiler having a combustion chamber of which all the side walls and the top wall are composed of steam generating tubes of substantially circular section, means to close all of said walls between said tubes to prevent the passage of the heating gases between said tubes except one wall through which the gases pass ontheir way to the exhaust flue.

8. A boiler having a combustion chamber of which all the side walls and the top wall are composed of steam generating tubes of substantially circular section, means to close all of said walls between said tubes to prevent the passage of the heating gases between said tubes except one wall through which the gases pass on their way to the exhaust flue, in combination with supplementary tubes over which the exhaust-gases from the combustion chamberpass so as to heat them by convection.

9. The boiler of claim 1 in combination with additional steam generating tubes heated by conbetween said tubes and each wall being in line 4. A boiler having a combustion chamber all tween said tubes, and each wall extending consaid tubes, and each wall extending continuously vection'from the gases passing out of the combustion chamber.

10. The boiler of claim 1 in combination with additional steam generating tubes located above the combustion chamber and heated by convection from the gases passing out of said chamber.

11. A boiler having a combustion chamber with five walls, four at the sides and one at the top, four of them being metal walls including steamgenerating tubes of substantially circular section and means to close said walls between said tubes .to prevent passage of the heating gases therebetween, the fifth also including steam-generating tubes and having openings through which the gases pass on their way to the exhaust flue.

12. A boiler having a combustion chamber with five'walls, four at the sides and one at the top, four of them being metal walls including steamgeneratlng tubes of substantially circular section and means to close said walls between said tubes to prevent passage of the heating gases therebetween, the fifth also including steam-generating tubes and having openings through which the .gases pass on their way to the exhaust flue, in

combination with supplementary tubes over which the exhaust gases from the combustion chamber pass so as to heat them by convection.

13. A boiler having a combustion chamber with five walls, four at the sides and one at the top, four of them being metal walls including steamgenerating tubes spaced apart with metal fillers between them to form closed metal walls and the fifth also including steam-generating tubes and having openings through which the gases pass on their way to the exhaust flue.

14. A boiler having a combustion chamber of which all the side walls and the top and bottom walls are metal walls including water tubes of substantially circular section, one of said walls, being open to permit the passage of gases to the exhaust flue, another being open to permit the discharge of ash and the remainder being closed between said tubes to prevent passage of gases therebetween.

15.. A boiler having a combustion chamber of which all the side walls and the top andbottom walls are metal walls including water tubes of substantially circular section, one of said walls being open to permit the passage of gases to the exhaust flue, another being open to permit the discharge of ash and the remainder having the tubes spaced apart with metal fillers between them to form closed metal-walls.

16., The boiler of claim 14, in combination with nozzle burners discharging into the combustion chamber.

the sides and the top of which are metal walls includingewater tubes or substantially circular section and exposed to the radiant heat of the burning fuel, and closing means between said tubes to prevent the passage of gases therebetween, said metal walls constituting a complete closure except for the openings for passage through the chamber of the fuel and its produc s.

18. A boiler having a combustion chamber the side walls of which comprise upright steam generating tubes of substantially circular section and are closed to prevent the passage of heating gases between the tubes and to form a complete enclosure with the tubes exposed to the radiant heat of the burning fuel in combination with additional tubes heated by convection from thegases passing out of the combustion chamber, said convection tubes being shielded from the radiant heat oi the burning fuel in the combustion chamber 1 9. A boiler having a combustion chamber the side walls 01' which comprise upright steam gen-- erating tubes of substantially circular section and are closed to prevent the passage of heating gases between the tubes and to form a complete enclosure with the tubes exposed to the radiant heat of the burning fuel in combination with additional substantially horizontal tubes located above the combustion chamber, heated by convection from the gases passing out of said'chambet and shielded from the radiant heat of the burningi'uel in the combustion chamber.

20, A boiler having a combustion chamber the side walls of which comprise upright steam generating tubesot substantially circular section and are closed to prevent the e of heating gases tion chamber and nozzle burners discharging into the combustion chamber so as to in suspension therein.

21. A steam generator comprising a combustion chamber and a number 01' convection heating tubes outside of said combustion chamber,

burn the fuel said combustion chamber having side walls and a top wall composed oi steam generating tubes of substantially circular section. one of said walls shielding said convection heating tubes from the direct radiant heat of combustion gases in said 5 combustion chamber, and one wall permitting passage 01 combustion gases from said combustion chamber. to said convection heating tubes. said walls being closed between said tubes, except for said passage from said combustion chamher to said convection heating tubes.

22. A steam generator comprising a combustion chamber and a number of convection heating tubes outside of said combustion chamber, said combustion chamber having side walls and a top wallcomposed of steam generating tubes 01 substantially circular section, one oi said walls shielding said convection heating tubes from the direct radiant heat or combustion gases in said combustion chamber, and one wall permitting passage of combustion gases from said combustion chamber to said convection heating tubes, said walls being closed between said tubes, except for a said passage from said combustion chamber to said convection heating tubes, and means secured to individual tubes for anchoring heat insulating material to said closed'wall.

JOSEPH B. MURRAY, 4 THOMAS E. MURRAY, Ja., Executors' of the Estate of Thomas E. Murray,

Deceased. 

